The amino acid conjugate formed by the interaction of the anion transport inhibitor 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS) with band 3 protein from human red blood cell membranes.

The specific anion transport inhibitor 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS) and its reduced analog (H2DIDS), when irreversibly bound to band 3 protein of the red blood cell membrane, form amino acid conjugates through interaction with the epsilon-amino group of a particular lysine residue. The specific residue is located in a transmembrane segment of band 3 protein and appears to be a close neighbor of the transport site.